Gold nanotubes used to image and destroy cancer cells

Pulsed near infrared light (shown in red) is shone onto a tumour (white) that is encased in blood vessels, while the tumor is imaged by multispectral optoacoustic tomography via the ultrasound emission (blue) from the gold nanotubes (Image: Jing Claussen/iThera Medical, Germany)

For some time, the potential of gold nanoparticles as a diagnostics and imaging tool has been known to scientists, but new research suggests they could prove even more useful than previously thought. A team at the University of Leeds has discovered that shaping the particles in the form of nanotubes sees them take on a number of new properties, including the ability to be heated up to destroy cancer cells.

At the heart of the approach's flexibility is a newly developed technique enabling the researchers to control the length of the gold nanotubes. The researchers say by altering how long the nanotubes are they can manipulate how they respond to different types of light.

More specifically, they can tailor the nanotubes to react to near-infrared light. To investigate its efficacy, the team administered the gold nanotubes intravenously in mice and tracked their movements using an imaging technique known as multispectral optoacoustic tomography (MSOT).

"When the gold nanotubes travel through the body, if light of the right frequency is shone on them they absorb the light," says Professor Steve Evans from the School of Physics and Astronomy at the University of Leeds. "This light energy is converted to heat, rather like the warmth generated by the Sun on skin. Using a pulsed laser beam, we were able to rapidly raise the temperature in the vicinity of the nanotubes so that it was high enough to destroy cancer cells."

The team found that the function of the gold nanotubes could be switched from regular imaging to cell-destruction mode by changing the brightness of the laser pulse. And because the nanotubes were excreted from the mouse's body, they weren't likely to create problems resulting from toxicity.

In addition to its cancer-destroying capabilities, the nanotubes also have the ability to carry drugs to the tumor site, offering another layer of flexibility. The researchers say the study is the first time the effects of the gold nanotubes have been observed in mice and are hopeful it could lead to more precise forms of treatment with reduced side effects.

"The nanotubes can be tumor-targeted and have a central hollow core that can be loaded with a therapeutic payload," says Dr James McLaughlan, one of the study's co-authors. "This combination of targeting and localized release of a therapeutic agent could, in this age of personalized medicine, be used to identify and treat cancer with minimal toxicity to patients.”

Pulsed near infrared light (shown in red) is shone onto a tumour (white) that is encased in blood vessels, while the tumor is imaged by multispectral optoacoustic tomography via the ultrasound emission (blue) from the gold nanotubes (Image: Jing Claussen/iThera Medical, Germany)